The present invention relates to an information signal regenerating stylus with its base applied with an electrode and a manufacturing method thereof. The stylus, detects an information signal as a variance of electrostatic capacity on a running disc recording medium (hereinafter called a "disc") in which said information signal is recorded as a variance in a geometrical shape.
As disclosed in Japanese Patent Laid-Open No. 140516/1979, the so-called electrostatic capacity system is considered at present for detection of an information signal as a variance of electrostatic capacity on a regenerating stylus with its base consisting of a diamond or the like applied with an electrode. This system includes a driven disc in which the information signal is recorded in sequence as a variance in geometrical shape so as to have a spiral recording locus, without providing particularly a recording signal channel to guide the regenerating stylus on the surface of the disc. According to this system, resolution can be improved by minimizing the electrode applied on the regenerating stylus in thickness and width as compared with a bit size corresponding to the information signal, and a constitution of a regeneration system is simplified as compared with an optical system wherein the information signal recorded in the disc is read optically, thus providing various advantages as known well. Many types of information signal regenerating styli for use on said electrostatic capacity system have been proposed in the industry concerned. For example, one proposed information signal regenerating stylus has an electrode part attached on one side of a stylus base shaped as a triangular pyramid and then cut in at the tip to a constant width in the wear direction. This regenerating stylus has its length in the direction of sliding to the disc increased as it is worn out and is thus not capable of coping with a deflection of the disc, resulting in a shape deterioration of the S/N ratio or a defect of dust sticking and stylus flying. Then, the length in the sliding direction of the regenerating stylus is limited according to the disc deflection, which is capable of marring the disc surface from a stylus pressure per unit area exceeding an allowable limit of an elasticity of the disc.
Another information signal regenerating stylus is formed by attaching the electrode part on one side of a stylus base in the shape of a pentagonal pyramid which is formed with a diamond or the like. This generating stylus needs a high precision on the tip and further requires that the stylus base be ground mechanically into the shape of a pentagonal pyramid, thus limiting mass production.